Security note: Research into Onion Browser suggests that browser content — including cookies — may be retained, depending on how an app is closed or if the app crashed. Users are encouraged to press the "New Identity" button before closing the app, as this will ensure that all session data in Onion Browser is wiped from the device.

November 11, 2014, Current Version: It's a two release week! Onion Browser 1.5.10 is a minor release which fixes some issues with configuring bridges, the display of the progress bar (which was not appearing in iOS 8), and adds a TLS "padlock" icon to show if a connection is entirely over TLS or if it contains insecure content. More details can be found in the CHANGES.txt file in GitHub. Details on security updates can be found in the Security page. Users are encouraged to update via App Store.

November 9, 2014, Previous Version: Onion Browser 1.5.9 fixed a crash on the DuckDuckGo .onion site over SSL — and other websites where the "Cannot Verify Website Identity" prompt appears. Further, SSLv3 was disabled to improve security and bypass the POODLE attack. Tor was updated to 0.2.5.10 and OpenSSL updated to 1.0.1j. More details can be found in the CHANGES.txt file in GitHub.

Download

Note: The app is currently unavailable in France due to import
regulations on encryption software. The app is unavailable and does not work
in China and Iran due to these nations blocking access to the Tor network.[‡]

‡: The obfsproxy transport
tool allows Tor to bypass these methods, but cannot be integrated into Onion Browser due to
the limited iOS App "single process" architecture.

Copies of Onion Browser downloaded outside the App Store —
via "jailbreak" app directories like Cydia — are built and
released by third parties and are not supported by the developer. These
copies may have modifications added by the packager, which may
interfere with your privacy or security. For the best security, you
should purchase the app; in situations where App Store payment is
difficult due to security precautions (i.e. using an alias in the App
Store that is not listed on a credit card), you may
e-mail the developer
to request an App Store download code. For best security in non-App
Store circumstances, you should
build your own copy of the app.

Bugs, Caveats, Side Notes

Using Onion Browser does not inherently guarantee security or privacy. It simply provides a set
of features that may enhance privacy and anonymity while browsing the web.
For more information: The Tor Project
maintains a small section about staying anonymous over Tor, as do
several
threads
on Reddit and other messageboard sites.

Disclaimer: Onion Browser only tunnels traffic
within the Onion Browser app. You are still using a smartphone,
and in extremely sensitive circumstances you should be aware that
iOS or your cellular provider may continue to leak non-Onion Browser
traffic and other information.

Video note:
Websites using
HTML5 <video> tags may leak
<video>-related DNS queries and data transfer outside
of Tor. This includes YouTube, Vimeo, and any website using
iOS-compatible HTML5 video. This is due to behavior of the embedded
QuickTime player and a comprehensive workaround has not yet been developed.

JavaScript blocking: The "Active Content Blocking" feature is experimental.
If ACB is turned off, JavaScript techniques can identify your
device even if User-Agent Spoofing is enabled.

Geolocation blocking: Websites may use the HTML5 Geolocation API unless the "Active Content Blocking" feature is set to "Block All". Users should remain
vigilant for any pop-ups asking for permission to access location data.

Common Sense: If you log into websites in Onion Browser that you normally log into
outside of the Tor network, they will a) still know who you are,
and b) know that you use Tor. In certain circumstances (i.e. political
dissent in repressive nations), this may be incriminating information
in itself.

Disclaimers, notices, etc.

"Onion Browser" is a trademark of Mike Tigas. Forks of this project must not
use the "Onion Browser" name when distributing binary forms of
this application.

Mike Tigas and OnionBrowser are not affiliated with nor endorsed by the Tor
Project. Onion Browser carries no guarantee from The Tor Project about
quality, suitability or anything else. ("Tor" is a registered
trademark of The Tor Project, Inc.)

This software uses strong cryptography and may it fall under certain
export/import and/or use restrictions in some other parts of the world.
BEFORE using any encryption software, please check your country's laws,
regulations and policies concerning the import, possession, or use,
and re-export of encryption software, to see if this is permitted.
See http://www.wassenaar.org
for more information.

If you are a developer and plan on redistributing this
app in source or binary form, please see read “ENCRYPTION NOTICE / APP DISTRIBUTION NOTES”
in the LICENSE file
for more detailed disclaimers.